In all of the earlier applications above referred to, there are disclosed toration techniques, i.e., techniques for fiberization of attenuable material by delivering a stream of the attenuable material in attenuable condition into the zone of interaction of a gaseous jet directed into a larger gaseous blast. All of the applications also identify various attenuable materials which may be fiberized according to the techniques disclosed; and it is pointed out that the techniques are particularly adapted to the fiberization of thermoplastic materials, especially thermoplastic mineral materials, such as glass, and reference hereinafter will frequently be made to the fiberization of glass, it being understood that other attenuable materials, such as thermoplastic organic materials, for instance poly vinyl alcohol, may be similarly fiberized.
Certain of the above prior applications also disclose arrangements providing for development of a zone of stable or laminar flow in the jet characterized by inflow of induced ambient gas (for instance air), the stream of softened or molten attenuable material being delivered into the influence of the jet in the region of the induced ambient gas entering the zone of laminar flow. In this way, the entry of the stream of attenuable material into the fiberizing center is stablized, and the stream of material is carried in the jet flow into the zone of interaction with the blast. For this purpose, prior U.S. Pat. No. 4,145,203 discloses the use of a jet guiding element introduced into the flow of the jet and having a curved surface operating as a Coanda guiding device, and which develops the desired laminar flow or stable low pressure zone in the jet into which the stream of glass is introduced. Similarly, prior U.S. Pat. No. 4,102,662 discloses a deflector plate for the same general purpose; and any of these and of similar guiding or deflecting devices, are preferably employed in the practice of the present invention.
The establishment of a zone of laminar flow with resultant induction of ambient air may alternatively be provided by employing a jet system comprising a pair of jets lying in a common plane and directed in said plane to impinge on each other at an acute angle, as disclosed in U.S. Pat. No. 4,159,199, issued June 26, 1979. The combined flow of the two jets is then directed into a blast in order to develop the desired zone of interaction and thereby effect fiberization by toration.
In considering certain of the objects and advantages of the invention, it is noted that in a typical glass fiberizing system, the means for developing and delivering the stream of molten material, frequently a glass melter or the forehearth of a glass melting furnace, is arranged with delivery orifices positioned to discharge streams of glass downwardly under the influence of gravity. It is further to be noted that in many situations, it is convenient from the standpoint of available space in the manufacturing facility, to develop a downwardly directed fiber-laden gaseous current which is intercepted by a horizontally moving perforated fiber-collecting conveyor. With these two factors in mind, the present invention utilizes a novel interrelationship of the basic components of the toration fiberizing centers, i.e., with the blast and jet generating devices preferably arranged toward opposite sides of the path of downward delivery of the streams of attenuable material. In addition, the blast generating device is preferably positioned to deliver the blast downwardly at one side of the plane of delivery of the glass streams, and the jet devices are positioned at the opposite side of said plane and are positioned to deliver the jets laterally into the blast.
The foregoing disposition of the basic components of the fiberizing centers (particularly the location of the blast and jet generating devices in positions located toward opposite sides of the plane in which the glass streams are delivered from the glass melting forehearth or other equivalent equipment) is advantageous in providing effective utilization of available plant production area and is also effective from the standpoint of convenient access to and avoidance of congestion of apparatus in the region of the fiberizing centers.
In addition to the advantages above mentioned, it is pointed out that the configuration of the fiberizing system above described, especially the downwardly directed blast and the horizontally moving fiber-collecting conveyor, provides another advantage. Thus, this configuration results in fiber lay-down on the conveyor with a high proportion of the fibers extended transversely of the plane of the fiber mat or blanket being formed. This results in production of mats or blankets having relatively high compressive strength, as is desired for many purposes, especially where board-like insulation products are being made.
In fiberizing centers with the components arranged in the manner above referred to, each stream of attenuable material is delivered into the influence of a laterally directed jet to be carried thereby into the zone of interaction of the jet with the blast. In the preferred practice of the invention, provision is made for deflecting the jet either by use of jet guiding or deflecting means or by employing twin jets, in order to establish stable laminar zones in the flow of the jets intermediate the jet orifices and the region of penetration of the jets into the blast, the streams of molten material being delivered into said laminar flow zones. In this way, fragmentation of the glass streams is avoided and stable feed is established, thereby providing for production of a single fiber in each fiberizing center.
In considering still another aspect of the present invention, attention is called to the fact that in certain configurations of the fiberizing centers employed in association with a downwardly delivered stream of molten glass, there is a tendency to develop upwardly or reversely directed currents of air in localized zones. Such currents are herein referred to as rejection currents; and in certain configurations, they tend to disrupt the normal downward feed of the glass stream, with consequent carrying of fragments of the glass upwardly and into contact with various structural parts of the fiberizing centers, such as the blast nozzle, or the jet nozzle or deflector.
In accordance with still another embodiment of the present invention, rejection currents of the kind above referred to are minimized by the employment of two different deflectors associated with the jet and arranged to jointly influence the jet flow, this multiple deflector system resulting in an increased jet deflection and also in minimizing the rejection currents.